I think it is a very important part, but I'm not sure if it would be considered the best way. Everyone has a different learning style, so it's best to find what works well for YOU. Listening will help you develop the accent, hear how to pronounce words, to identify words and grammatical structure. Speaking will give you a chance to demonstrate what you have been listening too and practice what you have learned. Writing will give you a chance to visualize or see the vocabulary, the usage and grammar, and even the letters to help you pronounce things.

to be honest,speaking is the best way to improve for me.now i am learning japanese and french,and just in the beginning,every day,i practise,English,Japanese and Franch,i get much improvement from it.also ENGLISH CORNER is a good place to go to if possible.

well, undoubtedly it's very effective . but besides speaking, please keep up  your listening and basic writing.